Timer

In computing and in embedded systems, a timer (also known as programmable interval timer (PIT)) is a counter that generates an output signal when it reaches a programmed count (or zero in case they are counting down). The output signal can trigger an interrupt. Timers can be up or down counting, and in many cases can be programmed to be single shot or multiple shot or simply continue once it has read the programmed count (or 0 in case of a down counter)